package com.jinhuhang.u2.util;

import android.graphics.Color;

/**
 * Created by OnionMac on 2017/10/17.
 */

public class ColorShadesUtil {
    /**
     * Source from :
     * https://gist.github.com/cooltechworks/4f37021b1216f773daf8
     * Color shades will provide all the intermediate colors between two colors. It just requires a decimal value between
     * 0.0 to 1.0
     * and it provides the exact shade combination of the two color with this shade value.
     * Textual explanation :
     * <p>
     * White          LtGray          Gray            DkGray           Black
     * 0               0.25            0.5             0.75            1
     * Given two colors as White and Black,and shade
     * as 0    gives White
     * as 0.25 gives Light gray
     * as 0.5  gives Gray
     * as 0.75 gives Dark gray
     * as 1    gives Black.
     */

    private int   mFromColor;
    private int   mToColor;
    private float mShade;

    public ColorShadesUtil setFromColor(int fromColor) {
        this.mFromColor = fromColor;
        return this;
    }

    public ColorShadesUtil setToColor(int toColor) {
        this.mToColor = toColor;
        return this;
    }

    public ColorShadesUtil setFromColor(String fromColor) {

        this.mFromColor = Color.parseColor(fromColor);
        return this;
    }

    public ColorShadesUtil setToColor(String toColor) {
        this.mToColor = Color.parseColor(toColor);
        return this;
    }

    public ColorShadesUtil forLightShade(int color) {
        setFromColor(Color.WHITE);
        setToColor(color);
        return this;
    }

    public ColorShadesUtil forDarkShare(int color) {
        setFromColor(color);
        setToColor(Color.BLACK);
        return this;
    }

    public ColorShadesUtil setShade(float shade) {
        this.mShade = shade;
        return this;
    }

    /**
     * Generates the shade for the given color.
     *
     * @return the int value of the shade.
     */
    public int generate() {
        int fromR = Color.red(mFromColor);
        int fromG = Color.green(mFromColor);
        int fromB = Color.blue(mFromColor);

        int toR = Color.red(mToColor);
        int toG = Color.green(mToColor);
        int toB = Color.blue(mToColor);

        int diffR = toR - fromR;
        int diffG = toG - fromG;
        int diffB = toB - fromB;

        int red = fromR + (int) ((diffR * mShade));
        int green = fromG + (int) ((diffG * mShade));
        int blue = fromB + (int) ((diffB * mShade));

        return Color.rgb(red, green, blue);
    }

    /**
     * Assumes the from and to color are inverted before generating the shade.
     *
     * @return the int value of the inverted shade.
     */
    public int generateInverted() {
        int fromR = Color.red(mFromColor);
        int fromG = Color.green(mFromColor);
        int fromB = Color.blue(mFromColor);

        int toR = Color.red(mToColor);
        int toG = Color.green(mToColor);
        int toB = Color.blue(mToColor);

        int diffR = toR - fromR;
        int diffG = toG - fromG;
        int diffB = toB - fromB;

        int red = toR - (int) ((diffR * mShade));
        int green = toG - (int) ((diffG * mShade));
        int blue = toB - (int) ((diffB * mShade));
        return Color.rgb(red, green, blue);
    }

    /**
     * Gets the String equivalent of the generated shade
     *
     * @return String value of the shade
     */
    public String generateInvertedString() {
        return String.format("#%06X", 0xFFFFFF & generateInverted());
    }

    /**
     * Gets the inverted String equivalent of the generated shade
     *
     * @return String value of the shade
     */
    public String generateString() {
        return String.format("#%06X", 0xFFFFFF & generate());
    }
}
